Client wanted to move ViewState off the page to reduce page weight. Hadn't done this for awhile (read ages) so I found this article and the discussion about where to move it to. So I went with cache and allow them to change it or turn it off completely.
It did help the page weight..decreased it by almost a third. I will do some timing tests to see what difference it has made. We're keeping 2 pages of data and monitoring to see if we need more.